Sleep apnoea and hypoventilation

OSA, or obstructive sleep apnoea/hypopnoea (OSAH) are currently the preferred terms for the problem of dynamic upper airway obstruction during sleep. OSA is part of a spectrum, with trivial snoring at one end and repetitive complete obstruction throughout the night (such that the patient cannot sleep and breathe at the same time). Along this spectrum is a point at which the degree of obstruction and the attendant arousal fragments sleep sufficiently to cause daytime symptoms. Distinction should be made between just the findings on sleep study of OSA episodes (OSA) and an abnormal sleep study plus the presence of symptoms (i.e. obstructive sleep apnoea syndrome, OSAS). Asymptomatic OSA is much more common than symptomatic (OSAS).